Hardened Valve Seats

[58 Apache]

I just purchased a '57 Ford with 312ci engine that was rebuilt.  Essentially zero miles on engine.  When I asked the seller if the rebuilder installed hardened exhaust valve seats, he didn't know.  When they first introduced ethanol during the oil embargo in the 1970's, it was called gasohol.  This was during the phase out of lead from gasoline.  I was building an internally balanced 383 Chevy small block with all the go fast goodies.  Bill Rogers of Roger's Performance in CC, TX advised me to install hardened exhaust valve seats in my "double hump" ported heads, but I blew him off. 

 

Six months later, My engine crapped itself running down Chapman Ranch Road at well over 100 mph.  When we pulled the heads, the exhaust valves had sunk about a quarter inch into the water jacket, which explained the gradual demise to poor performance and white smoke out the side pipes.  All the valves were sunk the same distance (SS valves) and were in excellent condition.  The exhaust valve seats looked as though they had been milled.  Bill just gave me that "told you so" look, and repaired the heads and installed hardened vale seats (exhaust).  He also showed me a pile of heads with the same problem.

 

My question is - has anyone driving a pre-'70 V8 car encountered this problem?  Lead was added to gasoline to reduce detonation, but a lot of knowledgeable machinists believed the elimination of lead to be the cause.  I ran premium gas, not gasohol, so that wasn't the issue.  Concentration wise, there was very little lead in gasoline.  I can't envision the process by which lead would protect exhaust valve seats, but many others swore it did but could not explain how.  I discussed the issue with the Conoco scientists at Ponca City, and they had no explanation either.

 

Anyone else had this problem?  I am trying to decide if I want to pull the heads on a brand-new engine in a freshly restored car to install hardened exhaust valve seats.

[Bloo]

In the late 80s or early 90s one of the hot rod magazines built some test engines and did some some direct comparisons. This was prompted by the removal of lead, rather than gasohol. I believe the original and most detailed article was in Popular Hot Rodding, but I can't remember for sure. Some of the others followed suit later on. I recall the conclusion was that the difference was insignificant and possibly unmeasurable in a normal street driven V8. Heavily loaded engines, drag racing, towing, motorhome, speedboat, etc. were more prone to valve seat recession and could benefit from hard seats.

 

The rub is that a lot can go wrong when using inserts. The machine work is critical and if not done right the inserts can fall out and hold a valve open which could punch a hole in a piston. I would also think this could happen if the head cracked. How many plain cast iron heads (without inserts) have you seen with a crack across the valve seat? I have seen quite a few. There are also some engines that simply don't have enough cast iron under the seat for a reliable insert job (Buick Nailhead comes to mind). My take is don't cut out perfectly machinable seats in favor of inserts for a street driven antique. If valve recession happens, then put the inserts in at that time. It probably wont happen.

 

 

Edited January 24, 2023 by Bloo (see edit history)

[58 Apache]

I keep telling myself the same thing, but recession is difficult to detect until serious damage is present.  I do have a bore scope.  I guess I could bore scope the cylinders and seats when I do my 6-month maintenance thing.

 

I have a '64 Corvair Turbo convertible in which a valve seat came loose.  Fortunately, damage was minimal.  I removed the turbo and heads and replaced with a complete two-carb setup.  The Corvair is due for a major refurbishment.  Unfortunately, it is about third in line.

 

I will hold off the hardened seats.  I would be pressed to put 2000 miles a year on the T'Bird.  I have to install AC first.

[Rusty_OToole]

In the seventies I saw lots of Chevy V8s with deep valve seat recession like you describe. Chrysler products had flame hardened valve seats and did not suffer this problem. Whether it was just the valve seats is another question, Chevy's castings were very rough and poor quality, and their cams looked like they were made of compressed tin foil or case hardened bread, and they wore out to beat the band.

 

If it was my car I would toss a little Redex, Marvel Mystery Oil, Bardahl or your favorite upper cylinder lubricant in the gas and hope for the best. If you don't drive it hard it should last a long time.

[John348]

From the looks of that T-Bird I don't think it is going to be getting much drive time, or hard driving time. My cars engines (all Chevy's) were rebuilt well over 20 years ago and I never had any problems. 

Edited January 24, 2023 by John348 (see edit history)

[58 Apache]

Did I mention I love W blocks?  I'm installing a Tri-Powered 409 (actually 424 ci) in a '58 Apache 3100.  It's a project I started long ago before I got married (again).   She's history and the engine is being assembled.  I already rebuilt the Muncie M22.  I found the Apache on a river bank, and the W block was an old truck motor from a junked water well driller.  The Apache will be a hot rod for this old man.  I can smell the burning rubber now.

 

Those weeds are growing in the truck.  Pic taken the day I picked it up fresh out of the swamp.

 

 

Look closely and you can see the relieved exhaust hardened seats.  CC'ing head chambers (17.6 cc's).

 

 

I had to fly cut the Ross forged pistons for valve clearance.  Had these made in 1993, still had the invoice ($846).  See the cant?

Edited January 24, 2023 by 58 Apache (see edit history)

[Fordy]

I was led to believe when doing my 24 Hupp engine that it didn't require the hardened seats as the motor was designed for unleaded (ie before it was an additive). So far no dramas

[Dandy Dave]

1 hour ago, Fordy said:

I was led to believe when doing my 24 Hupp engine that it didn't require the hardened seats as the motor was designed for unleaded (ie before it was an additive). So far no dramas

The 24 Hupp had a lower speed engine and less compression. You won't have any problems. I've driven my 1915 Buick on tours for the last 15 years and have not had any problems since I did a valve job on it when I first got it. Many other pre war cars are the same way. Where you run into problems is when your looking for high speed, high compression and the most HP you can get out of it.

[joe_padavano]

I think people lose a lot of sleep over hardened seats for no good reason. For a lightly-used showcar that may only get driven to cruise night on weekends, this is really unnecessary. The difference between hardened and regular seats is probably the difference between going 100,000 miles between valve jobs vs. 80,000 miles. You're unlikely to get to that point in your lifetime. Now, for a vehicle that's driven regularly, a race car, or a truck that's used like a truck (ie, more than a cooler and a couple of lawn chairs in the bed), then yeah, put them in.

[Rusty_OToole]

From my understanding valve seat recession occurs when a critical degree of heat is reached. This can happen because of the stress of high speed, high power required to pull a long hill with a heavy load, or if the engine is set up to run lean or the fuel burns hot. If you have a low compression low performance engine, and if you baby it, the exhaust valves may never reach that high a temp.

In any case a little extra oil can't hurt. Either as an upper cylinder oil type additive, or for low compression prewar engines, a percentage of kerosene or stove oil in the gas.

[Pfeil]

On 1/23/2023 at 5:13 PM, Bloo said:

In the late 80s or early 90s one of the hot rod magazines built some test engines and did some some direct comparisons. This was prompted by the removal of lead, rather than gasohol. I believe the original and most detailed article was in Popular Hot Rodding, but I can't remember for sure. Some of the others followed suit later on. I recall the conclusion was that the difference was insignificant and possibly unmeasurable in a normal street driven V8. Heavily loaded engines, drag racing, towing, motorhome, speedboat, etc. were more prone to valve seat recession and could benefit from hard seats.

 

The rub is that a lot can go wrong when using inserts. The machine work is critical and if not done right the inserts can fall out and hold a valve open which could punch a hole in a piston. I would also think this could happen if the head cracked. How many plain cast iron heads (without inserts) have you seen with a crack across the valve seat? I have seen quite a few. There are also some engines that simply don't have enough cast iron under the seat for a reliable insert job (Buick Nailhead comes to mind). My take is don't cut out perfectly machinable seats in favor of inserts for a street driven antique. If valve recession happens, then put the inserts in at that time. It probably wont happen.

 

 

What about VW and Porsche? Don't know about MB and BMW, however VW since 1937 and Porsche since 1948 have been using steel inserts with no problems. I personally have never seen one fall out of a VW head, and I worked in unit repair (engines and transaxles) for VW.

[joe_padavano]

21 minutes ago, Pfeil said:

What about VW and Porsche? Don't know about MB and BMW, however VW since 1937 and Porsche since 1948 have been using steel inserts with no problems. I personally have never seen one fall out of a VW head, and I worked in unit repair (engines and transaxles) for VW.

Kind of difficult to build an aluminum head that doesn't have hardened seats.

[31Buick96S]

I worked in a machine shop for 15 years from about 1981 to 1996.  The only two cases of exhaust valve recession that we saw had underlying causes. The first was a Ford 351M in an F150 that was used to tow a large camper.  It turned out that the distributor was at fault, the mechanical advance mechanism was corroded until it no longer functioned.  The second was a Chevrolet 350 that ran at the local dirt track in a Street Stock, the owner had a local carburetor "guru" rejet his carb and ended up running so lean that the valve seats sank about 3/8".  I rebuilt a Chevrolet 327 for a 1967 Camaro I had shortly after I started working there and frankly couldn't afford to have the hardened seats installed. I put over 125000 miles on the car and sold it to a friend. When he freshened up the motor a couple of years later, the valves and seats just needed touching up, no signs of seat recession.

[60FlatTop]

I live on the west side of Rochester, New York, over toward Buffalo. If I had a job requiring my to commute to Syracuse every day I would give valve seat recession a second thought, but only if I used the NYS Thruway.

[Pfeil]

3 hours ago, joe_padavano said:

Kind of difficult to build an aluminum head that doesn't have hardened seats.

You'll have to admit its a lot easier for a hardened seat to fall out of an aluminum head than an iron head.

[joe_padavano]

28 minutes ago, Pfeil said:

You'll have to admit its a lot easier for a hardened seat to fall out of an aluminum head than an iron head.

Absolutely.

[junkyardjeff]

I have been running a 235 Chevy six for over 20 years with no issues,now it does have bad valve stem seals that lubricate the valves. Like others said just add MMO or possibly a little 2 cycle oil if you are worried.

[58 Apache]

In my case, I suspect the cause to have been high compression, operating near the threshold of detonation, and constant balls to the wall use.  I drove the car to work, and I worked just past Kingsville.  My path took me down Chapman Ranch Road, 16 miles long with only a couple of curves.  I routinely drove in excess of 100 mph there and back, a total of 50 miles one way.  The car was a 1968 'Vette convertible with an internally balanced 383 built for street racing.  It had 10.5 to 1 CR, open Hooker headers and side pipes, air shocks, wire wheels, Ross forged pistons, polished and shot-peened rods, Holley 750 DP on a 2" spacer, 2.02 and 1.68 valves, ported 64cc Double Hump'ers, Offenhouser dual plane intake manifold, Super Coil, Mallory distributor/ignition, Comp Cam cam (0.224 @ 0.050 on 108 advanced 4 degrees) and valve train, and a Muncie M22 with a McLoed clutch and pressure plate.  It had those vacuum operated flip-up headlights, and at about 130 mph, they would open on their own.  Anything over that and she got a bit squirrelly.  If you shined a black light into the interior, it lit up like a Christmas tree.

[carbking]

When I pumped gasoline at a Standard Oil (Amoco to you youngsters) in the mid-1960's, we were told that all Standard Oil gasoline was unleaded. We sold a LOT of gasoline!

 

I frequently get the corollary to the original question, that being should I add a lead supplement?  My standard answer for a passenger car is no. Race cars, heavy trucks, buses, motorhomes, require more information.

 

Jon

[58 Apache]

I pumped gas at a Billups station.  Lowest price was $0.17/gal during a gas war (1966).

[Frank DuVal]

On 1/23/2023 at 7:13 PM, Bloo said:

I recall the conclusion was that the difference was insignificant and possibly unmeasurable in a normal street driven V8. Heavily loaded engines, drag racing, towing, motorhome, speedboat, etc. were more prone to valve seat recession and could benefit from hard seats.

Yep, which leads to the question

 

On 1/23/2023 at 6:47 PM, 58 Apache said:

My engine crapped itself running down Chapman Ranch Road at well over 100 mph.

are you going to run this Tbird at 100 MPH all the time like you ran that Chevy engine? If so, yes, you need hardened valve seats. If driven like a normal collector car (quiet Ed!) forget about it.

[Frank DuVal]

3 hours ago, carbking said:

in the mid-1960's, we were told that all Standard Oil gasoline was unleaded. We sold a LOT of gasoline!

Also very true. Hence why it was called white gas and could be used in Coleman stoves,  B & S engines, etc. Yes, I recall the plate on the side of lawn mowers with B&S engines saying to use white gas.

[58 Apache]

2 hours ago, Frank DuVal said:

Yep, which leads to the question

 

are you going to run this Tbird at 100 MPH all the time like you ran that Chevy engine? If so, yes, you need hardened valve seats. If driven like a normal collector car (quiet Ed!) forget about it.

Old age caught up with me.  I am the slowest guy on the Interstate now.  I seldom hit the speed limits.  In my youth, I had a need for speed and WOT was my friend.  That 'Vette was built to run.  Several years ago, I built a blown alcohol Harley KHK for Bonneville.  With the 30% loss of HP at 4200 feet ASL, the speed I was going to hit was about what that 'Vette would do.  Still, I decided to find a pilot, preferably a very light one.  Haven't made it to the salt flats to date.  Still looking for a knowledgeable, and willing, cam grinder.

 

The T'Bird is a cruiser.  Boo and I will cruise the boulevard in style.

 

 

[arcticbuicks]

i just use additive in gas,and no need for hardened valve seats

[Dandy Dave]

7 hours ago, Frank DuVal said:

Also very true. Hence why it was called white gas and could be used in Coleman stoves,  B & S engines, etc. Yes, I recall the plate on the side of lawn mowers with B&S engines saying to use white gas.

I could not tell you how many of those Briggs and Strattons I have had to try to lock to the seats down in. Especially when a rat built a nest in one over the winter and it was run first time in the spring. 🙃 I plumb run out of fingers and toes. 😬

[joe_padavano]

14 hours ago, carbking said:

When I pumped gasoline at a Standard Oil (Amoco to you youngsters) in the mid-1960's, we were told that all Standard Oil gasoline was unleaded. We sold a LOT of gasoline!

 

I frequently get the corollary to the original question, that being should I add a lead supplement?  My standard answer for a passenger car is no. Race cars, heavy trucks, buses, motorhomes, require more information.

 

Jon

That is true. Amoco sold unleaded (including high test) long before hardened valve seats were a thing. I doubt most people ever noticed a difference.

[carbking]

Since I worked at the station, got a 2 cent (gas was about 35 cents) per gallon discount, so we used it in everything. My Corvette, Dad's truck and motorhome, and the family passenger car all used unleaded gasoline with no issues.

 

We have had to grow older, and have "experts" explain to us the problems we should have had (but didn't)!

 

Jon

[60FlatTop]

22 minutes ago, carbking said:

and have "experts" explain to us the problems we should have had (but didn't)!

 

[JamesR]

I like the Marvel Mystery oil solution, but I don't really like running MMO through the carb. The oiliness attracts dirt/etc. over time. I've run it through the carb occasionally, but I don't really like even doing that. Does anyone use one of those drip systems for MMO? Any drawbacks to that? Some folks have said that if you drive moderately, you don't even need MMO. I have a '54 Ford and early '60's mercury, engines not rebuilt.

[Str8-8-Dave]

I'm gonna guess that Chevy was expected to produce maximum output under maximum load with a modified cam, heavy valve springs, lots of RPM, lots of ignition timing advance, and maybe, too high fuel octane.

 

The fuel comment is because most hot rodders think if they are running super high performance engines they should automatically use the highest octane fuel they can find.  Octane additives are designed to raise the flash point of gasoline to prevent pre-ignition.  The other, not well understood characteristic is the fact they have slower flame propagation rates than lower octane fuels.  The combustion cycle is slowed by higher octane and if the octane is too high the combustion cycles doesn't complete before the exhaust valve opens and that arrangement will fry exhaust valves and destroy valve seats.  The correct fuel, the fuel that will produce best engine performance, is just high enough octane to prevent preignition and low enough octane to allow the combustion cycle to complete before the exhaust valve opens.  Once that exhaust valve opens, conduction heat transfer that keeps valve and valve seat temperatures under control along with the high cylinder pressure that produces the power you are looking for is lost.  If the combustion cycle hasn't completed extremely high temperature fuel/air combustion is now taking a blow torch to the valves and seats and blowing out the exhaust headers.  

 

Okay, now, let's consider what the 312 Ford Y-block engine is going to have to contend with.  Are you going to try to drag-race that T-bird?  Are you going to drive it wide open throttle often? Ever? 

 

Running the 312 with just good enough fuel to keep it from detonating/knocking, driving the car at reasonable speeds and not beating on it, it will probably do just fine without hardened seats. 

 

Another approach would be to find out who builds engines for Amos Minter's T-bird restorations and ask them if they routinely put in hard seats in 292/312 Ford Y-blocks prepped for Minter's award-winning Birds.  

Edited February 1, 2023 by Str8-8-Dave (see edit history)